Increment: Cancel all async-tasks when closing LocalFileTransferActivity

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/local_file_transfer/DeviceListFragment.java

@@ -90,6 +90,10 @@ public class DeviceListFragment extends ListFragment implements WifiP2pManager.P
   private InetAddress fileReceiverDeviceAddress;  // IP address of the file receiving device
   private boolean fileTransferStarted = false;
 
+  private PeerGroupHandshakeAsyncTask peerGroupHandshakeAsyncTask;
+  private SenderDeviceAsyncTask senderDeviceAsyncTaskArray[];
+  private ReceiverDeviceAsyncTask receiverDeviceAsyncTask;
+
   @Override
   public void onActivityCreated(@Nullable Bundle savedInstanceState) {
     super.onActivityCreated(savedInstanceState);
@@ -192,6 +196,20 @@ public class DeviceListFragment extends ListFragment implements WifiP2pManager.P
     ((WifiPeerListAdapter) getListAdapter()).notifyDataSetChanged();
   }
 
+  void cancelAsyncTasks() {
+    if(peerGroupHandshakeAsyncTask != null) {
+      peerGroupHandshakeAsyncTask.cancel(true);
+    }
+
+    if(senderDeviceAsyncTaskArray != null) {
+      for(SenderDeviceAsyncTask task : senderDeviceAsyncTaskArray) {
+        task.cancel(true);
+      }
+    } else if(receiverDeviceAsyncTask != null) {
+      receiverDeviceAsyncTask.cancel(true);
+    }
+  }
+
   public void onInitiateDiscovery() { // Setup UI for searching peers
     searchingPeersProgressBar.setVisibility(View.VISIBLE);
     frameLayoutPeerDevices.setVisibility(View.INVISIBLE);
@@ -203,7 +221,8 @@ public class DeviceListFragment extends ListFragment implements WifiP2pManager.P
     /* Devices have successfully connected, and 'info' holds information about the wifi p2p group formed */
     groupInfo = info;
     // Start handshake between the devices
-    new PeerGroupHandshakeAsyncTask(this, groupInfo).execute();
+    peerGroupHandshakeAsyncTask = new PeerGroupHandshakeAsyncTask(this, groupInfo);
+    peerGroupHandshakeAsyncTask.execute();
   }
 
   public void setClientAddress(InetAddress clientAddress) {
@@ -225,7 +244,8 @@ public class DeviceListFragment extends ListFragment implements WifiP2pManager.P
     if(groupInfo.groupFormed && !fileSender) {
       displayTransferProgressFragment();
 
-      new ReceiverDeviceAsyncTask(this, transferProgressFragment).execute();
+      receiverDeviceAsyncTask = new ReceiverDeviceAsyncTask(this, transferProgressFragment);
+      receiverDeviceAsyncTask.execute();
 
     } else if(groupInfo.groupFormed) {
       {
@@ -237,8 +257,10 @@ public class DeviceListFragment extends ListFragment implements WifiP2pManager.P
         showToast(localFileTransferActivity, R.string.preparing_files, Toast.LENGTH_LONG);
         for(int i = 0; i < 20000000; i++);
 
+        senderDeviceAsyncTaskArray = new SenderDeviceAsyncTask[totalFilesForTransfer];
         for(int i = 0; i < totalFilesForTransfer; i++) {
-          new SenderDeviceAsyncTask(this, transferProgressFragment, i).execute(fileUriList.get(i));
+          senderDeviceAsyncTaskArray[i] = new SenderDeviceAsyncTask(this, transferProgressFragment, i);
+          senderDeviceAsyncTaskArray[i].execute(fileUriList.get(i));
         }
       }
     }

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/local_file_transfer/LocalFileTransferActivity.java

@@ -269,6 +269,11 @@ public class LocalFileTransferActivity extends AppCompatActivity implements Wifi
 
   @Override
   public void closeLocalFileTransferActivity() {
+    final DeviceListFragment deviceListFragment = (DeviceListFragment) getSupportFragmentManager().findFragmentById(R.id.fragment_device_list);
+    if(deviceListFragment != null) {
+      deviceListFragment.cancelAsyncTasks();
+    }
+
     fileSendingDevice = false;
     disconnect();
     this.finish();

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/local_file_transfer/PeerGroupHandshakeAsyncTask.java

@@ -50,9 +50,8 @@ class PeerGroupHandshakeAsyncTask extends AsyncTask<Void, Void, InetAddress> {
   @Override
   protected InetAddress doInBackground(Void... voids) {
 
-    try {
+    if(groupInfo.groupFormed && groupInfo.isGroupOwner && !isCancelled()) {
-      if(groupInfo.groupFormed && groupInfo.isGroupOwner) {
+      try (ServerSocket serverSocket = new ServerSocket(PEER_HANDSHAKE_PORT)) {
-        ServerSocket serverSocket = new ServerSocket(PEER_HANDSHAKE_PORT);
         serverSocket.setReuseAddress(true);
         Socket server = serverSocket.accept();
 
@@ -60,20 +59,24 @@ class PeerGroupHandshakeAsyncTask extends AsyncTask<Void, Void, InetAddress> {
         Object object = objectInputStream.readObject();
 
         // Verify that the peer trying to communicate is a kiwix app intending to transfer files
-        if (isKiwixHandshake(object)) {
+        if (isKiwixHandshake(object) && !isCancelled()) {
           if(BuildConfig.DEBUG) {
             Log.d(TAG, "Client IP address: "+ server.getInetAddress());
           }
           exchangeFileTransferMetadata(server.getOutputStream(), server.getInputStream());
-          server.close();
+
           return server.getInetAddress();
 
         } else { // Selected device is not accepting wifi direct connections through the kiwix app
           return null;
         }
+      } catch (Exception ex) {
+        ex.printStackTrace();
+        return null;
       }
-      else if(groupInfo.groupFormed) { //&& !groupInfo.isGroupOwner
+    }
-        Socket client = new Socket();
+    else if(groupInfo.groupFormed && !isCancelled()) { //&& !groupInfo.isGroupOwner
+      try (Socket client = new Socket()) {
         client.setReuseAddress(true);
         client.connect((new InetSocketAddress(groupInfo.groupOwnerAddress.getHostAddress(), PEER_HANDSHAKE_PORT)), 15000);
 
@@ -82,19 +85,17 @@ class PeerGroupHandshakeAsyncTask extends AsyncTask<Void, Void, InetAddress> {
 
         exchangeFileTransferMetadata(client.getOutputStream(), client.getInputStream());
 
-        client.close();
-
         return groupInfo.groupOwnerAddress;
-      }
-      else {
-        return null;
-      }
 
       } catch (Exception ex) {
         ex.printStackTrace();
         return null;
       }
     }
+    else {
+      return null;
+    }
+  }
 
   private boolean isKiwixHandshake(Object object) {
     return (object.getClass().equals(String.class) && object.equals(HANDSHAKE_MESSAGE));
@@ -143,6 +144,10 @@ class PeerGroupHandshakeAsyncTask extends AsyncTask<Void, Void, InetAddress> {
       }
   }
 
+  @Override protected void onCancelled() {
+    Log.d(TAG, "PeerGroupHandshakeAsyncTask cancelled");
+  }
+
   @Override
   protected void onPostExecute(InetAddress inetAddress) {
     deviceListFragment.setClientAddress(inetAddress);

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/local_file_transfer/ReceiverDeviceAsyncTask.java

@@ -45,14 +45,13 @@ class ReceiverDeviceAsyncTask extends AsyncTask<Void, Integer, Boolean> {
 
   @Override
   protected Boolean doInBackground(Void... voids) {
-    try {
+    try (ServerSocket serverSocket = new ServerSocket(FILE_TRANSFER_PORT)) {
-      ServerSocket serverSocket = new ServerSocket(FILE_TRANSFER_PORT);
       if(BuildConfig.DEBUG) Log.d(TAG, "Server: Socket opened at " + FILE_TRANSFER_PORT);
 
       final String KIWIX_ROOT = deviceListFragment.getZimStorageRootPath();
 
       int totalFileCount = deviceListFragment.getTotalFilesForTransfer();
-      for(int currentFile = 1; currentFile <= totalFileCount; currentFile++) {
+      for(int currentFile = 1; currentFile <= totalFileCount && !isCancelled(); currentFile++) {
 
         Socket client = serverSocket.accept();
         if(BuildConfig.DEBUG) Log.d(TAG, "Server: Client connected for file " + currentFile);
@@ -78,9 +77,11 @@ class ReceiverDeviceAsyncTask extends AsyncTask<Void, Integer, Boolean> {
         publishProgress(SENT);
         deviceListFragment.incrementTotalFilesSent();
       }
-      serverSocket.close();
 
-      return true;  // Returned in case of a succesful file transfer
+      if(isCancelled())
+        return false; // Returned in case the task was cancelled
+      else
+        return true;  // Returned in case of a successful file transfer
 
     } catch (IOException e) {
       Log.e(TAG, e.getMessage());
@@ -94,6 +95,10 @@ class ReceiverDeviceAsyncTask extends AsyncTask<Void, Integer, Boolean> {
     transferProgressFragment.changeStatus(fileItemIndex, fileStatus);
   }
 
+  @Override protected void onCancelled() {
+    Log.d(TAG, "ReceiverDeviceAsyncTask cancelled");
+  }
+
   @Override
   protected void onPostExecute(Boolean allFilesReceived) {
     if(BuildConfig.DEBUG) Log.d(TAG, "File transfer complete");

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/local_file_transfer/SenderDeviceAsyncTask.java

@@ -55,9 +55,13 @@ class SenderDeviceAsyncTask extends AsyncTask<Uri, Void, Boolean> {
   @Override
   protected Boolean doInBackground(Uri... fileUris) {
     Uri fileUri = fileUris[0];    // Uri of file to be transferred
-    Socket socket = new Socket(); // Represents the sender device
+    ContentResolver contentResolver = deviceListFragment.getActivity().getContentResolver();
 
-    try {
+    try (Socket socket = new Socket(); InputStream fileInputStream = contentResolver.openInputStream(fileUri)) { // Represents the sender device
+
+      if(isCancelled()) {
+        return false;
+      }
       socket.bind(null);
 
       String hostAddress = deviceListFragment.getFileReceiverDeviceAddress().getHostAddress();
@@ -67,9 +71,6 @@ class SenderDeviceAsyncTask extends AsyncTask<Uri, Void, Boolean> {
 
       OutputStream socketOutputStream = socket.getOutputStream();
 
-      ContentResolver contentResolver = deviceListFragment.getActivity().getContentResolver();
-      InputStream fileInputStream = contentResolver.openInputStream(fileUri);
-
       DeviceListFragment.copyToOutputStream(fileInputStream, socketOutputStream);
       if(BuildConfig.DEBUG) Log.d(TAG, "Sender: Data written");
 
@@ -78,16 +79,11 @@ class SenderDeviceAsyncTask extends AsyncTask<Uri, Void, Boolean> {
     } catch (IOException e) {
       Log.e(TAG, e.getMessage());
       return false;
+    }
+  }
 
-    } finally {
+  @Override protected void onCancelled() {
-      if (socket.isConnected()) {
+    Log.d(TAG, "SenderDeviceAsyncTask cancelled");
-        try {
-          socket.close();
-        } catch (IOException e) {
-          e.printStackTrace();
-        }
-      }
-    }
   }
 
   @Override